Optical character recognition (OCR) systems are used to transform images or representations of paper documents, for example document files in the Portable Document Format (PDF), into computer-readable and computer-editable and searchable electronic files. A typical OCR system includes an imaging device that produces the image of a document and software that runs on a computer that processes the images. As a rule, this software includes an OCR program, which can recognize symbols, letters, characters, digits, and other units and save them into a computer-editable format—an encoded format.